The present invention relates generally to systems for controlling and/or improving the quality of aquatic environments.
The present invention also relates to aquatic treatment systems for biologically removing nutrients and other materials from water.
The present invention also relates to synthetic structures for promoting and/or controlling the growth of aquatic species.
Systems for improving aquatic habitats are referred to in U.S. Pat. No. 5,669,330 (O""Hare), U.S. Pat. No. 5,639,657 (Saiki), U.S. Pat. No. 4,950,104 (Streichenberger), U.S. Pat. No. 4,818,579 (Uchida) and U.S. Pat. No. 4,441,453 (McMickle). A floating open ocean farm system is referred to in U.S. Pat. No. 5,309,672 (Spencer). A system for cultivating crustaceans in water is described in U.S. Pat. No. 3,841,266 (Hoshino).
The present invention relates to a neutrally buoyant synthetic aquatic structure. The structure may be used to treat a body of water by removing nutrients and other materials from the water. According to another aspect of the invention, the synthetic structure may be used to promote and/or control the growth of aquatic species in a body of water.
In a preferred embodiment of the invention, the neutrally buoyant synthetic structure is formed of flexible buoyant material connected to a denser-than-water ballast portion. The ballast portion is suspended from the buoyant material to stabilize and orient the synthetic structure. The buoyant material may have a high surface area structure for promoting biological growth. The ballast portion does not sink to the bottom of the body of water. Consequently, the high surface area structure may be maintained in the photic zone.
The high surface area structure may be formed of a variety of materials, including but not limited to needle punched thread, open cell foam, polyolefin or spun polyester batting and microporous granular particles.
The ballast portion may be formed of a heavy wire enclosed in the flexible buoyant material. The ends of the wire may be used to connect the synthetic structure to another, similarly constructed synthetic structure. Alternatively, a polyester rope may be used along the bottom edge of the synthetic structure to connect multiple synthetic structures end to end. According to another aspect of the invention, the ballast portion may include granular material, such as sand or gravel. The sand or gravel may be measured to provide the desired neutral buoyancy for the synthetic structure.
The present invention also relates to a synthetic structure for providing food for fish and other biological species. The structure may be provided with a flexible active portion for promoting biological growth, and a ballast portion for stabilizing the synthetic structure in the water. In a preferred embodiment of the invention, the synthetic structure as a whole is neutrally buoyant such that the flexible active portion is maintained in the photic zone.
According to one aspect of the invention, a flexible connecting portion may be used to connect the ballast portion to the flexible active portion. The connecting portion may be used to promote neutral buoyancy of the entire structure. The connecting portion may be formed, for example, of a fibril material. The connecting portion may be formed, if desired, of a spun polyester batting material that promotes biological growth. The material for the connecting portion itself may be neutrally buoyant. The material preferably should be durable to withstand product lifetimes of three to four years or more.
As an alternative to the structures described above, the invention may be practiced without a separate flexible connecting portion.
The present invention also relates to a method of controlling an aquatic environment.
The present invention may be used to achieve a variety of objectives. For example, the neutrally buoyant synthetic structure may be used to remove excess nutrients from a freshwater pond, for example on a golf course. Controlling the amount of nutrients in the water is an efficient technique for preventing algal growth on the pond surface.
The neutrally buoyant structure may also be used to provide food and improve the quality of water in a commercial aquaculture sea pen.
The synthetic structure may be formed of a variety of materials, including flexible sheets, panels and/or ribbons. Separate layers may be used to perform separate buoyancy and water treatment/control functions.
An object of the invention is to provide a synthetic aquatic structure that is easy to handle and that maintains its biologically active portion in a stable position in the photic zone of a body of water.
Another object of the invention is to provide a method of using a synthetic structure to biologically control or improve the quality of an aquatic environment.
Another object of the invention is to provide a system for generating food, controlling water quality and providing shelter in an aquatic environment.
Another object of the invention is to encourage and support the production of a natural, regenerative food source for successful aquaculture production under a wide variety of conditions.
Another object of the invention is to provide a durable and economical system for simultaneously providing both food and shelter for aquatic species, for example for aquaculture purposes. By providing food and shelter in the same structure, a viable population of a given aquatic species may be maintained in a concentrated area.
Another object of the invention is to provide a system that can be economically adapted and tailored for different uses and conditions. For example, the growth of organisms may be enhanced by selectively modifying the surface structure and/or by providing desired nutrients in the surface structure. In addition, desired bacteria may be selectively implanted in the high surface area structure to create the desired biological effect in the water.
Another object of the invention is to reduce the reliance on formulated feeds in aquaculture operations. Such formulated feeds may omit important cofactors which are critical to immune function. The present invention may be used to provide a complete, natural diet for aquatic species.
Another object of the invention is to provide an economical and convenient system for biologically removing undesired or excessive nutrients and/or toxins from water. According to one aspect of the invention, both aerobic and facultatively anaerobic reactions may occur simultaneously and in close proximity to one another.
The term xe2x80x9cneutrally buoyantxe2x80x9d synthetic structure, as used herein, means a synthetic structure that has an overall density that is the same as or slightly less than the density of the supporting fluid. The supporting fluid may be seawater or fresh water, for example. In a preferred embodiment of the invention, the overall specific gravity of the neutrally buoyant synthetic structure (considering all the component parts of the structure, including the ballast portion, the active portion, etc.) is in a range of from (1) essentially equal to the specific gravity of the supporting fluid to (2) about 0.15 less than the specific gravity of the supporting fluid.
The xe2x80x9cneutrally buoyantxe2x80x9d nature of the synthetic structure causes it to operate in the supporting fluid according to the following three conditions: (1) the structure does not sink to the benthos (provided the depth of the supporting fluid is sufficiently greater than the height of the structure); (2) the structure floats near the surface of the supporting fluid; and (3) no more than a small portion of the structure extends above the surface of the supporting fluid.
Other features, objects and advantages of the invention will become apparent from the following detailed description and drawings illustrating preferred embodiments of the invention.